@techreport{oai:ipsj.ixsq.nii.ac.jp:00231871,
 author = {Takahiro, Suzuki and Akira, Suzuki and Yuma, Tamura and Xiao, Zhou and Takahiro, Suzuki and Akira, Suzuki and Yuma, Tamura and Xiao, Zhou},
 issue = {8},
 month = {Jan},
 note = {Consider a graph G where each vertex has a threshold. A vertex v in G is activated if the number of active vertices adjacent to v is at least as many as its threshold. A vertex subset A0 of G is a target set if eventually all vertices in G are activated by initially activating vertices of A0. The Target Set Selection problem (TSS) involves finding the smallest target set of G with vertex thresholds. This problem has already been extensively studied and is known to be NP-hard even for very restricted conditions. In this paper, we analyze TSS and its weighted variant, called the Weighted Target Set Selection problem (WTSS) from the perspective of parameterized complexity. Let k be a solution size and l be the maximum threshold. We first show that TSS is W[1]-hard for split graphs when parameterized by k + l, and W[2]-hard for cographs when parameterized by k. We also prove that W[2]-hard for trivially perfect graphs when parameterized by k. On the other hand, we show that WTSS can be solved in O(n log n) time for complete graphs. Additionally, we design FPT algorithms for WTSS when parameterized by nd + l, tw + l, and ce, where nd is neighborhood diversity, tw is treewidth, and ce is cluster editing number., Consider a graph G where each vertex has a threshold. A vertex v in G is activated if the number of active vertices adjacent to v is at least as many as its threshold. A vertex subset A0 of G is a target set if eventually all vertices in G are activated by initially activating vertices of A0. The Target Set Selection problem (TSS) involves finding the smallest target set of G with vertex thresholds. This problem has already been extensively studied and is known to be NP-hard even for very restricted conditions. In this paper, we analyze TSS and its weighted variant, called the Weighted Target Set Selection problem (WTSS) from the perspective of parameterized complexity. Let k be a solution size and l be the maximum threshold. We first show that TSS is W[1]-hard for split graphs when parameterized by k + l, and W[2]-hard for cographs when parameterized by k. We also prove that W[2]-hard for trivially perfect graphs when parameterized by k. On the other hand, we show that WTSS can be solved in O(n log n) time for complete graphs. Additionally, we design FPT algorithms for WTSS when parameterized by nd + l, tw + l, and ce, where nd is neighborhood diversity, tw is treewidth, and ce is cluster editing number.},
 title = {Parameterized Complexity of Weighted Target Set Selection},
 year = {2024}
}